Method and apparatus for encoding/decoding image data

ABSTRACT

The invention relates to a method and an apparatus for encoding images, more particularly to an encoding unit in conjunction with a library of pictorial entities and image qualifiers. The method and apparatus provide encoding an image by using a code factor table in conjunction with a set of element codes. The resulting image code allows the set pictorial elements of an image and their associated image qualifiers to be represented by a compact code uniquely representing a given configuration of pictorial elements. The use of the resulting image code facilitates the transmission and storage of images requiring only the code to be sent or stored. The invention further provides a computer readable medium comprising a program element that direct a computer to implement the encoding process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 09/322,932, now U.S. Pat.No. 6,690,830, filed on May 28, 1999, the contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to a method and apparatus for encoding/decodingimage data. It is particularly applicable to the encoding/decoding ofimages that can be separated into their constituent parts as may be usedin composite picture systems used in law enforcement, artisticcreations, recreation and education.

BACKGROUND

It is known in the art to create images on the basis of components thatare assembled to form a complete image. For example, a common techniquefor synthesizing single images of faces involves horizontally dividingthe image of a face into bands for different features or the face suchas hair, eyes, nose, mouth, and chin, respectively. Paper stripscontaining exemplary features are then be combined to form a compositedrawing of a face. Yet another example involves a program elementrunning on a computing platform which allows a user to select individualcomponents and combining them on a pre-selected face. In a typicalinteraction, the user first selects the shape of the face then eyes,nose, mouth and other components and combines them to form a facialimage. Many variations on this theme can be used as described inKakiyama et al. U.S. Pat. No. 5,600,767, Yoshino et al. U.S. Pat. No.5,644,690, Sato et al. U.S. Pat. No. 5,537,662 and Belfer et al. U.S.Pat. No. 5,649,086 whose contents are hereby incorporated by reference.For example, the Sato et al. Patent, entitled Electronic Montagecomposing apparatus, describes a system for creating a montage image ofa face using a plurality of basic parts stored in a library.

In constructing an image, pictorial entities are selected from a libraryof pictorial entities as assembled into images. These images may then bestored on a computer readable medium commonly referred to as a databaseor repository. Often, the storage of an image requires significantamounts of memory, often necessitating large repositories. For example,a composite picture system used in a police department often requiresmaintaining records of thousands of individuals. The images aretypically stored in files in some graphical format such as a “bitmap”,“gif” or “jpeg” are other format. Although such encoding schemes providea compressed representation of the image, the memory required forstoring the image remains significant. In addition, compression methodsof the type described above generally degrade the quality of the image.The size and quality of images is also particularly significant when theimages are transmitted from one site to another via a digital link. Forexample, a given police station may transmit a composite picture toanother police station in order to share information about a givensuspect.

Thus, there exists a need in the industry to refine the process ofencoding images such as to reduce the memory requirements for storageand the bandwidth required for the transmission of the image.

SUMMARY OF THE INVENTION

The invention provides a novel method and an apparatus for encodingimages.

For the purpose of the specification, the expression “basic elements” isused to describe a part of a specific image. In the preferredembodiment, a basic element is comprised of a pictorial entityconditioned by a set of image qualifiers. Examples of pictorial entitiesin a facial image are noses, eyes, mouths and eyebrows. In the preferredembodiment, pictorial entities are grouped into classes. For example, incomposite picture system, all nose pictorial entities are grouped intothe “NOSE” class and all the eye pictorial entities are grouped in the“EYE” class. Each class of pictorial entities is associated to a set ofimage qualifiers that are used to condition the pictorial entities inthe associated class. The image qualifiers may include positionqualifiers, zoom qualifiers, color qualifier and the likes.

For the purpose of this specification, the basic elements used in thespecial case of a facial image are referred to as “basic morphologicalelements”.

For the purpose of this specification, the word “symbol” is used todesignate a representation of an object, image, qualifier or the likes.In a specific example, a symbol may be an index mapped to a memorylocation storing data elements such as a pictorial entity or imagequalifier.

According to a broad aspect, the invention provides, a computer readablestorage medium comprising a program element suitable for use on acomputer having a memory. The program element is operative to create afirst input to receive a set of element codes. The element codescharacterized a portion of an image and included at least one symbol. Agiven symbol is a representation of a certain characteristic of theportion of the element code. A given symbol can acquire a set ofpossible values indicative of variations of the certain characteristicwith which it is associated. The program element is also operative tocreate a second input to receive code factors associated to respectivesymbols of the set of element codes. A given code factor is assigned avalue that exceeds the highest value that the symbol with which it isassociated can acquire. The program element is operative to process theset of element codes to derive an image code. The image code is acompressed digital representation of the image, and is derived at leastin part on the basis of the plurality of code factors. The image codecan then be released as the output.

In a preferred embodiment, the image code is a number in a given base.Preferably, a large base is used in order to obtain a reduced number ofcharacters in the image code.

In a preferred embodiment of the invention, the encoding method andapparatus is integrated into a picture system. The picture systemcreates images on the basis of images of basic individual parts, hereinreferred to as basic elements. In the preferred embodiment, the picturesystem includes a library of pictorial entities and qualifiers, an imagebuilder unit, an encoding unit, a decoding unit and a factor table.

Each basic element in an image is assigned a unique identifier, hereinreferred to as element code. The element code contains information dataelements, herein referred to as symbols. In a specific embodiment, theelement code for each basic element includes a symbol that characterizesthe pictorial element. In a preferred embodiment, the element codeincludes a plurality if symbols. In a specific example two (2) symbolsare used namely an pictorial entity symbol and a position qualifiersymbol. The element code may contain additional symbols withoutdetracting from the spirit of the invention. For example symbolsrepresentative of other image qualifiers may be used such as color, zoomand other image effects may be used. An image is constructed by a set ofbasic elements. The basic elements present in a given facial image aresaid be “active” in the given image. The set of active elements isstored in a data structure suitable for that purpose. In a specificexample this data structure is an image data table. The image data tablestores for each class a record, each record containing a set of fields,each field describing the active pictorial entity and qualifiers.

The number variations in each of the symbols for each of the classes isstored in a table, herein referred to as a code factor table. The codefactor table provides information about the number of possiblevariations in an image. For each class, the code factor table stores arecord, each record containing a set of fields, each field describing amaximum factor. The maximum factor in the code factor table is thelargest identifier used for the given factor. Each symbol in the imagedata table is mapped to a factor in the code factor table.

According to another broad aspect, the invention provides an apparatusfor encoding an image, the image comprising a set of basic elements,each basic element of the set of basic elements being associated to anelement code. An encoding unit receiving as input the code factors andthe element codes. The encoding unit processes the set of element codesto derive an image code, the image code being a compressed digitalrepresentation of the image derived at least in part on the basis ofsaid plurality of code factors. The encoding unit then outputs the imagecode.

According to another broad aspect, the invention provides a method forencoding an image, the image comprising a set of basic elements, eachbasic element of the set of basic elements being associated to anelement code. A processing step receives as input the code factors andthe element codes to derive an image code. The image code is acompressed digital representation of the image derived at least in parton the basis of said plurality of code factors. The image code is thereleased.

In a preferred embodiment, the image code can be used to reproduce theimage described by the image code. Image data may be obtained bycombining the code factors and the image code with a decoding device.The image data is obtained by applying the inverse operations in thereverse order than those applied in the encoding process to the imagecode.

The image code allows each image to be described with a very smallnumber of characters permitting the rapid transmission of the image overa data transmission medium. The receiving device has a decoding unitthat is capable of extracting data information from the image code.

According to another broad aspect, the invention provides a method,apparatus and computer readable medium for decoding an image, the imagecomprising a set of basic elements, each basic element of the set ofbasic elements being associated to an element code. A processing stepreceives as input the code factors and the image code to derive theelement codes. The element codes are then released.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present invention will become apparentfrom the following detailed description considered in connection withthe accompanying drawings. It is to be understood, however, that thedrawings are designed for purposes of illustration only and not as adefinition of the limits of the invention for which reference should bemade to the appending claims.

FIG. 1 shows an apparatus including an embodiment of the invention;

FIG. 2 shows a high-level block diagram of functional units of the imagesystem including an image encoder in accordance with the spirit of theinvention;

FIG. 3 shows a high-level block diagram of functional units of the imagesystem including an image decoder in accordance with the spirit of theinvention;

FIG. 4 shows a detailed block diagram of the encoding process inaccordance with the spirit of the invention;

FIG. 5 shows a detailed block diagram of the decoding process inaccordance with the spirit of the invention;

FIGS. 6 a and 6 b show flow diagrams for the creation of an image andthe facial code in accordance with an embodiment of the invention;

FIG. 7 shows an alternative apparatus including an embodiment of theinvention;

FIG. 8 shows apparatuses including an embodiment of the inventionconnected by a data transmission medium.

DETAILED DESCRIPTION

In the preferred embodiment, the encoding method and apparatus inaccordance with the invention is integrated into a picture system forcreating images on the basis of images of individual parts, hereinreferred to as basic elements. For the sake of simplicity, thespecification will describe an embodiment of the invention integratedinto a composite picture system. It is to be understood that theencoding method and apparatus may be used in systems for creating imageson the basis of individual constituent parts other than a compositepicture system without detracting from the spirit of the invention.

In a preferred embodiment, as shown in FIG. 1, the composite picturesystem includes a general-purpose digital computer including a processor100 linked to a machine-readable storage element 108 that may be in theform of a mass storage device such as a hard-drive, a CD-ROM or anyother suitable storage medium. The system further includes a device forvisualizing the facial image such as a computer monitor 110 or aprinting device. The preferred embodiment also provides data input onwhich a user interface 112 is supported in order to allow the user toselect through a touch screen, keyboard, pointing device or other inputmeans, the individual basic morphological elements and to view thecombined result on the display screen 110. The latter 110 is likely tobe part of the data input. Optionally, the system further provides adata transmission medium 114 such as a telephone line, LAN, digitalcable, optical cable, wireless transmission device or any other suitablemeans for transmitting an image from the general purpose digitalcomputer to a receiving device. The computer readable medium 108 storingthe composite picture system includes of a set of modules namely alibrary of pictorial entities and image qualifiers 104 and programinstructions 102 interacting with the library of pictorial entities andimage qualifiers to create a facial image. The computer readable medium108 may also include symbols where each symbol is associated to arespective one of the pictorial entities and image qualifiers in thelibrary of pictorial entities and image qualifiers 104. The computerreadable medium further comprising a set of code factors, each codefactor being associated to a set of symbols, a given code factor beinglarger that the largest symbol in the set with which it is associated.The computer readable medium further comprises an encoding programelement 116 to encode a facial image.

In the preferred embodiment the composite picture system comprises anelectronic library of pictorial entities and image qualifiers 104. Eachpictorial entity in the library is an image of a facial part or anaccessory such as glasses, earrings or other. The pictorial entities inthe library 104 are organized into morphological classes, each classdescribing a part of the face. In a preferred embodiment, the followingbasic morphological classes are used: hairstyle, forehead, eyebrows,eyes, nose, mouth, chin, moustache, beard, wrinkles and glasses. Thepictorial entities are stored on a computer readable medium. The imagesmay be compressed in a format suitable for graphical storage such as abitmap (BMP), GIF of JPEG file format. Other file formats may be usedhere without detracting from the spirit of the invention.

In the preferred embodiment, each pictorial entity is identified with apictorial entity symbol. Typically, the pictorial entity symbol is asequence of alphanumeric characters. The pictorial entity symbols arestored on a computer readable medium in the database of symbols. Eachimage qualifier in the library is a characteristic of a correspondingclass. The image qualifiers in the library 104 may be organized intoqualifier types, each qualifier type describing a certain characteristicof the pictorial entity. In a preferred embodiment, the followingqualifier types are used: position and color. Other image qualifierssuch as zoom and the likes may be used without detracting from thespirit of the invention. The image qualifiers are stored on a computerreadable medium. In the preferred embodiment, each image qualifier isidentified with an image qualifier symbol. Typically, the imagequalifier symbol is a sequence of alphanumeric characters. The imagequalifier symbols are stored on a computer readable medium in thedatabase of symbols.

In a preferred embodiment, a basic morphological element includes apictorial entity and a set of image qualifiers. The image qualifierscondition the pictorial entity to alter the visual effect of the latter.For example the image qualifier may modify the position, color zoom orany other visual effect of the pictorial entity. The purpose of thespecification, the expression “basic morphological element” is used torefer to the pictorial entity conditioned by the image qualifiers. Eachbasic morphological element is associated to an element code. Theelement code contains a set of symbols. In a specific example, theelement code for each basic morphological element includes two (2)symbols namely a pictorial entity symbol and a position qualifiersymbol. The pictorial entity symbol identifies the pictorial entitywithin a given class in the library of pictorial entities and imagequalifiers. Preferably, the pictorial entities of a given class are eachassigned a unique symbol. The symbols need not be consecutive providedthey can be ordered and the largest symbol assigned to a pictorialentity of a given class can be determined. The position qualifier symbolprovides information on the position of the pictorial entity in thefacial image. Preferably, the number of possible positions for apictorial entity of a given class is predetermined. In a specificexample, there may be 5 possible positions for the eyes in a facialimage. Each position is assigned a position qualifier symbol such as anumber from 1 to 5 and each position qualifier symbol corresponds to aposition the pictorial entity with which it is associated can acquire.The element code may contain additional symbols without detracting fromthe spirit of the invention. For example, the element code may contain a“zoom” qualifier indicating the zoom level of the pictorial entity.

A facial image is constructed by a set of basic morphological elements.The basic morphological element present in a given facial image is saidbe “active” in the given image. The set of active basic morphologicalelements is stored in a data structure suitable for that purpose. In aspecific example this data structure is an image data table. The imagedata table stores for each class a record. Each records describes anelement code, each record containing a set of fields, each fielddescribing the pictorial entity symbol, position qualifier symbol andany other symbol. The entries in the image data table are referred to asactive element symbols. The table below shows a specific example of animage data table.

Pictorial entity Position qualifier Class symbol symbol EYES 34 2 LIPS 21 GLASSES 111 17

As shown above, a basic morphological element of class “EYES” with apictorial entity symbol “34” which is positioned at position “2” isactive in the facial image.

The number variations in each of the symbols for each of the classes isstored in a table, herein referred to as a code factor table. The codefactor table provides information about the number of possiblevariations in a facial image. For each class, the code factor tablestores a record, each record containing a set of fields, each fielddescribing a maximum factor. The maximum factor in the code factor tableis the largest symbol assigned to an image qualifier or pictorial entityfor a given class. Alternatively, the maximum factor is larger that thelargest symbol assigned to an image qualifier or pictorial entity for agiven class. This will best be understood in conjunction with a specificexample. The table below shows an example of a code factor table.

Maximum pictorial Maximum position Class entity factor qualifier factorEYES 900 5 LIPS 600 26 GLASSES 200 23

In the above table, there are three classes namely “EYES”, “LIPS” and“GLASSES” having “900”, “600” and “200” pictorial entities respectivelyas their maximum factor. In this specific example, the pictorialentities are assigned numerical symbols no larger that the maximumfactor for each respective class. In the case where pictorial entitiesare not assigned consecutive numerical symbols, the second column wouldcontain the largest pictorial entity symbol assigned to the pictorialentities of the respective class. The third column includes the maximumposition qualifier factor. Class “LIPS” for example has “26” as ismaximum position qualifier factor. In this specific example, positionsfor the individual pictorial entities are pre-determined. Eachpre-determined position is given a numerical position symbol that isbetween 1 and the maximum position qualifier factor in the code factortable.

As shown in FIG. 2, a facial code 206 for a given facial image may becreated by combining the code factors 200 and the image data 202 with anencoding device 204. In a preferred embodiment, the encoding device 204derives the facial code in accordance with the process described in FIG.4.

The facial code is first initialized at a based value 400. Preferably,this base value is zero (0). Following this, the encoding method beginswith the first class of the pictorial entities 402 and the first symbolof the element code of the class 404. The facial code is firstmultiplied 406 by the corresponding factor value in the code factortable. An example in conjunction with the factor table below will betterillustrate this step 406.

Maximum pictorial Maximum position Class entity factor qualifier factorEYES 900 5 LIPS 600 26 GLASSES 200 23

If class “EYES” for the pictorial entity is being considered, then thefacial code is multiplied by the pictorial entity factor “900”.Following this, the pictorial entity symbol from the image data table isadded 408 to the facial code. An example in conjunction with the imagedata table below will better illustrate this step 408.

Pictorial entity Position qualifier Class symbol symbol EYES 34 2 LIPS 21 GLASSES 111 17

If class “EYES” for pictorial entity is being considered, then thepictorial entity symbol “34” is added to the facial code. The systemthen proceeds to step 410 that checks if there are any symbols remainingfor the current class. In the affirmative, the system proceeds to step412 that determines which symbol to consider next. In the example above,the following symbol to consider is the position qualifier symbol. Thesystem then restarts at step 406. In the event that all symbols for thecurrent class have been processed, step 410 is answered in the negativeand the system proceeds to step 414. Step 414 checks if there are anyclasses remaining. In the affirmative the system proceeds to step 416that determines which class to consider next. In the example above, thenext class to consider is the “LIPS” class. The system then restarts atstep 404 with the first symbol of the element code of the new class. Inthe event that all classes have been processed, step 414 is answered inthe negative and the system proceeds to step 418 with the completefacial code.

As a variant, the facial code may be further comprise version numberinformation for the purpose of differentiating between different versionnumbers of the composite picture system. This in turn permits to insurethat a composite picture system using the facial code produced by theprocess described above is not induced in error if its version is notthe same than that of the composite picture system that created theimage. In a specific example, the version number information isintegrated to the facial code by multiplying the code by a specificnumber.

In the preferred embodiment, the facial code is a number in a givenbase. Preferably, a large base is used in order to obtain a reducednumber of characters in the facial code. In a specific example, thefacial code is a number in base “62” with characters {0–9, a–z, A–Z}.Other bases may be used without detracting from the spirit of theinvention. It is to be noted that the computations in steps 406 and 408of the encoding process may result in very large numbers in the order of10E+66 or bigger for large systems. It may therefore be preferable toprovide some specialized functions for the computation of themultiplication and addition operations for these numbers in order toavoid the possibility of overflow. The implementation of suchcomputations will be readily available to the person skilled in the artto which this invention pertains.

As a variant, characters in the facial code that may be visuallyconfusing are replaced by non-alphanumeric characters. For instance theletter “O” and the number “0” are similar in appearance as are theletter “I”, the letter “l” and the digit “1”. In a specific example, thecharacters in the facial code that may be visually confusing arereplaced by non-alphanumeric characters such as “+”, “=”, “@” and soonce the code is computed.

In a preferred embodiment, the facial code can be used to reproduce thefacial image described by the facial code. As shown in FIG. 3, facialimage data 304 may be obtained by combining the code factors 200 and thefacial code 302 with a decoding device 300. The facial image data 304 isobtained by applying the inverse operations in the reverse order thanthose applied in the encoding process to the facial code. In a preferredembodiment, the decoding device 300 derives the facial image data 804 inaccordance with the process described in FIG. 5.

The facial code is first obtained 500. Following this, the decodingprocess begins with the last class of the pictorial entities 502 and thelast symbol of the element code of that class 504. The facial code isfirst divided 506 by the factor value in the code factor tableassociated to the symbol being considered. An example in conjunctionwith the factor table below will better illustrate this step 506.

Maximum pictorial Maximum position Class entity factor qualifier factorEYES 900 5 LIPS 600 26 GLASSES 200 23

If a class “GLASSES” for the position qualifier is being considered,then the facial code is divided by the factor “23”. Following this, theremainder of the division performed in step 506 is stored as thecorresponding position qualifier symbol in the image data table 508. Thesystem then proceeds to step 510 that checks if there are any symbolsremaining for the current class. In the affirmative, the system proceedsto step 512 that determines which symbol to consider next. In theexample above, the following symbol to consider is the pictorial entitysymbol. The system then restarts at step 506. In the event that allsymbols for the current class have been processed, step 510 is answeredin the negative and the system proceeds to step 514. Step 514 checks ifthere are any classes remaining. In the affirmative the system proceedsto step 516 that determines which class to consider next. In the exampleabove, the next class to consider is the “LIPS” class. The system thenrestarts at step 504 with the last symbol of the element code of the newclass. In the event that all classes have been processed, step 514 isanswered in the negative and the system proceeds to step 518 with theimage data table including the complete description of the imagedescribed by the facial code. The image data table can then be used bythe composite picture system to access the library of pictorial entitiesand image qualifiers 104 and produce a facial image.

As shown in FIG. 3, the image data 304 is stored in an image data tablethat can be accessed by an image builder unit 306. The image builderunit 306 accesses the library of pictorial entities and image qualifiers104 of the composite picture system to extract the pictorial entitiesspecified by the image data. The image builder also extracts the imagequalifiers specified by the image data and is operative to condition thepictorial entities on the basis of the these extracted image qualifiers.Following this the builder unit 300 outputs an image which may bedisplayed to the user of the composite picture system. Extracting dataelements from a database on the basis of symbols is well known in theart to which this invention pertains.

In the event that the facial code comprises version number information,the reverse operation used to imbed the version number in the facialcode is applied to the facial code during the decoding process. In aspecific example where the version number information is integrated inthe facial code by multiplying the code by a specific number, thedecoding process involves dividing the facial code by that number.

In the event that characters in the facial code that may be visuallyconfusing were replaced by non-alphanumeric characters, the reverseoperation is performed on the facial code.

An example of a typical interaction will better illustrate thefunctionality of the encoding module implemented by the programinstructions 102 of composite picture system and using the datacomponents 104 106.

In a typical interaction, as shown in FIG. 6 a, once the compositepicture system is activated 600, the user selects a set of pictorialentities 602 through a user interface. The interface to the compositepicture system may be a keyboard, pointing device, touch screen or anyother suitable input means. The received input may be an address of thememory location where a given pictorial entity is located or some otherway of identifying it. The selection is entered in the image data tablein association with corresponding qualifier symbols. Preferably, thepictorial entities in a given class as assigned default qualifiersymbols. Once the system has received the request, the entries in theimage data table are used to locate in the library of pictorial entitiesand image qualifiers, the entries corresponding with the received input.When pictorial entity or image qualifier is selected it is considered tobe active. Following this, the selected pictorial entities and imagequalifiers are combined to form a facial image. The combination isperformed by positioning each active pictorial entity in a same frame atthe location specified by the position qualifier in the image datatable. The system then displays the facial image to allow the user toview it 604. Alternatively, after each selection of a pictorial entity,the systems displays it to allow the user to view the image as it standswith the current selection of pictorial entities. At condition 606, ifthe user is satisfied with the appearance of the facial image, thecomposite picture is complete 610. The completeness of the image may beindicated by a user inputting a command indicative that the image iscomplete. The image data table is then processed by the encoding processto compute the facial code 612. The user of the system may then make useof the facial image and facial code as he pleases. For example, the usermay print the resulting facial image, he may store the image by storingthe facial code computed at step 612 or he may transmit the image to anexternal site by transmitting the facial code. In the event that theuser is not satisfied with the appearance of the facial image, condition606 is answered in the negative and the user may modify the facial image608. The modification of the facial image may comprise differentoperations. For example, the user may replace a pictorial entity byanother of the same class; he may remove a pictorial entity alltogether; the element may be displaced in the vertical or horizontaldirection. In a specific example, the user interface may include ameans, such as arrows in the user interface, for displacing thepictorial entities in the vertical and horizontal directions. The arrowsmay be linked to functional modules that modify the position of theselected image in the screen. When the pictorial entity is displaced,the corresponding position qualifier symbol in the image table is alsomodified such as to reflect to current positioning of the pictorialentity. The user may select via a pointing device or other input meansthe element he wishes to displace in the facial image. The user thenuses the displacement arrows to position the pictorial entity in thedesired position in the facial image. Many variations in the userinterface are possible and implementations different from the onepresented above do not detract from the spirit of the invention. Forevery modification performed in step 608, the image data table isupdated accordingly. Once the facial image has been modified byselecting a revised set of pictorial entities and image qualifiers, thelatter are combined to form a facial image. The system then displays thefacial image as described in the image data table to allow the user toview it at step 604. Alternatively, after each selection of a pictorialentity or and image qualifier, the systems displays it to allow the userto view the updated image as it stands with the current selection. Theprocess continues until the user is satisfied with the image andcondition 606 is answered in the affirmative the system proceeds to step610.

As a variant, as shown in FIG. 6 b, the facial code may be computedincrementally as the user selects pictorial entities and imagequalifiers and modifies the facial image. Following step 602, the imagedata table is processed 652 by the encoding unit to compute the facialcode corresponding to the data in the image data table. The facial imagemay then be modified in accordance with steps 604 606 and 608 describedpreviously. Following step 608, the image data table is reprocessed bythe encoding unit 650 to compute the facial code corresponding to theupdated data in the image data table. In this variant, the facial codefor the image being created is computed as the user creates the image.Once the use stops entering new modifications, the code is readilycomputed without the need for the user to input a command indicativethat the image is complete.

In another typical interaction, the composite picture system may receiveas input the facial code describing a facial image. Using this facialcode, the composite picture system reconstructs the facial image.Therefore, the user interface may also include a means for entering thefacial codes. The facial code is first decoded by the process describedin connection with FIG. 5. The decoding process produces an image datatable containing information for generating the facial image. The systemaccesses the library of pictorial entities and image qualifiers andextracts the pictorial entities and image qualifiers corresponding tothe data contained in the image data table. The image is then displayedto the user which may make use of it as he please by modifying it,storing it, printing it or transmitting it.

FIG. 7 shows an alternative embodiment of an apparatus including anembodiment of the invention. Such an apparatus comprises a userinterface 706 such as a touch screen, mouse, keyboard are any othersuitable input means for communicating with the user of the imagesystem. The user interface communicates with an image builder unit 702operative to generate graphical data on the bases of a given set ofinput data elements. The image builder unit may be implements on ageneral purpose computing platform running an application software ofmay be a dedicated CPU unit programmed specifically for the purpose ofgenerating images. The Image builder unit 702 communicates with anoutput unit 704 such as a display unit or a printer unit to send thegenerated graphical data for output to the user. The image builder unitalso communicates with a library of pictorial entities and imagequalifiers 700. The library of pictorial entities and image qualifiers700 may be implemented on a computer readable medium such as a harddisk, CD-ROM, non-volatile RAM or any other suitable device. The imagebuilder unit 708 also communicates with a computer readable mediumincluding image data 708. The image data specifies the pictorialentities that are active in the given image as well as any otherrelevant image qualifier such as position and zooming. The image data708 may also be modified by the image builder unit 702 to update itsentries on the basis of inputs received by the image builder unit 702from the user through the user interface 706. The image data 708 can beaccessed by and encoder 710 operative to encode the image data accordingto the process described in this specification. The encoder may beimplemented on a general purpose computing platform running anapplication software in accordance with the process described or may bea dedicated CPU unit programmed specifically for the purpose of encodingimage data. The encoder 710 outputs the image code. The encoder mayfurther communicate with a communication unit 716 such as a modem,network card or any other suitable communication devices suitable fortransmitting data information over a communication channel 718. Theimage data 708 can be accessed by a decoder 714 operative to decode animage code according to the process described in this specification. Thedecoder 714 may be implemented on a general purpose computing platformrunning an application software in accordance with the process describedor may be a dedicated CPU unit programmed specifically for the purposeof decoding image codes. The decoder 714 outputs the image data that isinputted to the computer readable medium containing image data. Thedecoder may further communicate with the communication unit 716 in orderto receive image codes. The encoder 710 and decoder 714 also communicatewith a computer readable medium including element code factors 712.

The facial code produced by the process described above allows eachfacial image to be described with a very small number of characterscompared to a graphical representation permitting the rapid transmissionof the composite picture over data transmission medium. For example, asshown in FIG. 8, a police station at site A 804 using an embodiment ofthe invention can transmit the entire composite picture of a suspect topolice station at site B 802 by simply sending the facial code for thatfacial image either verbally or through an electronic communicationmeans 800. At the reception, police station at site B 800 enters thecode into the composite picture system that displays the compositepicture. The data transmission medium 800 between site A 802 and site B804 may be a telephone line with a set of modems, and Ethernetconnection, the Internet or any other communication medium suitable forthe transfer of data. In the above example, site A 804 and site B 802have on their local site a composite picture system of the typedescribed in FIG. 1 or FIG. 7 of the drawings. A copy of the library ofpictorial entities and image qualifiers is stored at each site and onlythe code needs to be transferred. Advantageously, the invention furtherallows the storage of a facial image by storing the facial code only ona computer readable medium. This may result in substantial savings interms of memory requirements for storing the images since only a singleinstance of each pictorial entity and image qualifier needs he stored,the instance being in the library of pictorial entities and imagequalifiers.

Although the present invention has been described in considerable detailwith reference to certain preferred versions thereof, other versions arepossible. For example, the method and apparatus described may be used ina system to encode a given image provided the image is build on thebasis of constituent parts. In these types of application the library ofpictorial entities and image qualifiers would include the appropriateset of pictorial entities and image qualifiers. Therefore, the spiritand scope of the appended claims should not be limited to thedescription of the preferred versions contained herein.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

1. A method, comprising: accessing a database of morphological elements,each of said morphological elements having at least one correspondingelement code representative of a part of an image, each element codebased on: (a) a symbol representative of a facial feature, the symbolhaving one of a plurality of values indicative of variations of thefacial feature, and (b) a first code factor having a value that equalsor exceeds a maximum value of the plurality of values indicative of thevariations of the facial feature; forming a representation of apredetermined facial image by combining morphological elements from thedatabase; determining a facial image code from the element codes of thecombined morphological elements; and transmitting said facial imagecode.
 2. The method of claim 1, wherein said forming a representation ofa predetermined facial image comprises: selecting combinations ofmorphological elements that together form the representation of theface; and determining said corresponding element codes to eachmorphological element.
 3. The method of claim 1, wherein said databaseof morphological elements comprises: a library of facial images.
 4. Themethod of claim 3, wherein said facial features comprise eyes, noses,wrinkles, mouth, ears, hair, hairstyle, facial shape, chin, or facialhair.
 5. The method of claim 3, wherein said facial features compriseeyeglasses, jewelry, or head wear.
 6. The method of claim 1, whereinsaid database of morphological elements comprises a library of imagequalifiers.
 7. The method of claim 6, wherein said library of imagequalifiers comprises visual effects applied to an image.
 8. The methodof claim 7, wherein said visual effects comprise enlarging, detracting,positioning, or coloring.
 9. A computer software product that includes amedium readable by a processor, the medium having stored thereon: animage information of a plurality of elements; a qualifier information ofa plurality of spatial relationships between said plurality of elements;and a sequence of instructions which, when executed by said processor,causes said processor to connect at least one element to at least onespatial relationship, wherein said sequence of instructions includes, asan attribute, combining at least other element with at least one otherspatial relationship with said at least one element and at least onespatial relationship, wherein said combining forms a facial image.
 10. Acomputer-readable medium having stored thereon a plurality of sequencesof instructions, said plurality of sequences of instructions includingsequences of instructions which, when executed by a processor, causesaid processor to perform: receiving a predetermined selection of eitheran element from image information or a spatial relationship fromqualifier information; obtaining link information corresponding to aselected element or spatial relationship, wherein the link informationincludes a user's selection as an attribute of the link information;displaying elements linked with a selected spatial relationship insequence according to the user's selection using the link information,if an element is selected for browsing; and displaying spatialrelationships which describe elements linked with a selected spatialrelationship in sequence according to the user's selection using thelink information, if a spatial relationship is selected, wherein saiddisplaying elements and displaying spatial relationships comprisesdisplaying a facial image.
 11. The method of claim 1, wherein each ofthe element codes further includes: an image qualifier having one of aplurality of values indicative of variations of a position of the facialfeature in the facial image; and a second code factor having a valuethat equals or exceeds a maximum value of the plurality of valuesindicative of the variations of the position of the facial feature inthe facial image.
 12. The method of claim 1, wherein the facial imagecode includes information indicative of a version number of a programused to perform one or more operations of the method.
 13. The method ofclaim 1, wherein the facial image code includes letters corresponding tothe at least one symbol and the first code factor.
 14. The method ofclaim 1, wherein the facial image code includes non-alphanumericcharacters substituted for visually confusing alphanumeric characters.15. A method for encoding a digital representation of a face,comprising: (a) multiplying a facial code by a first code factorcorresponding to a pictorial entity representing a facial feature, thefirst code factor having a value that equals or exceeds a maximum valueof a plurality of values indicative of variations of the facial feature;(b) adding a value of a symbol corresponding to the pictorial entity tothe facial code; (c) repeating (a) and (b) for one or more additionalpictorial entities, each corresponding to a different facial feature;and (d) combining results of (a)–(c) to form a facial code thatcorresponds to the digital representation of the face.
 16. The method ofclaim 15, wherein the pictorial entity symbol corresponds to one of theplurality of values indicative of variations of the facial feature andis less than said maximum value.
 17. The method of claim 15, furthercomprising after (b): identifying an additional symbol corresponding tothe facial feature and related to the pictorial entity; multiplying thefacial code by a second code factor corresponding to the additionalsymbol, the second code factor having a value that equals or exceeds amaximum value of a plurality of values indicative of variations of thepictorial entity; and adding a value corresponding to the additionalsymbol to the facial code.
 18. The method of claim 17, wherein theadditional symbol is an image qualifier symbol indicating a position ofthe facial feature represented by the pictorial entity in the digitalrepresentation of the face.